The present invention relates, in general, to racemic or enantiomerically enriched benzoyl piperidine compounds and pharmaceutically useful salts thereof, a pharmaceutical composition comprising an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds to treat central nervous system diseases and a method of treating central nervous system diseases in a mammal. More particularly, the present invention relates to racemic or enantiomerically enriched O-carbamoyl, alkoxy, azole or carbonate benzoyl piperidine compounds and pharmaceutically useful salts thereof, useful to treat the diseases of the central nervous system such as psychosis and cognition disorder. Also, the present invention is concerned with a process for preparing the same.
Many reports have disclosed that benzoyl piperidine compounds are effectively used for controlling various central nervous system (CNS) disorders, especially as antipsychotic and analgesics.
1-[n-(2-alkylthio-10H-phenothiazin-10-yl)alkyl]-4-benzoylpiperidines were disclosed in U.S. Pat. No. 4,812,456 and 6,7-dihydro-3-phenyl-1,2-benzisoxazol-4(5H)-ones and -ols were disclosed in U.S. Pat. No. 5,114,936. These compounds are found to be very effective as therapeutical medicines for managing CNS disease, such as antipsychotic and analgesics.
Active research and development efforts have been continued to be directed to the application of benzoyl piperidine compounds for the treatment of CNS disorders.
A principal object of the present invention is to provide racemic or enantiomerically enriched benzoyl piperidine compounds, represented by the following structural formula (I) and pharmaceutically acceptable salts thereof: 
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl;
X is selected from the group consisting of O-carbamoyl, straight or branched chain alkoxy of from 1 to 4 carbon atoms, imidazole, triazole, tetrazole and carbonate; and
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms.
More specifically, the present benzoyl piperidine compounds represented by the above formula (I) comprises racemic or enantiomerically enriched compounds represented by the following structural formula (V), (VIII), (XIV), and (XVI): 
wherein
n is 0 ; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R1 and R2 may be the same with or different from each other and are independently selected from the group consisting of hydrogen, methoxy, benzyl and 5 to 7-membered aliphatic cyclic compounds: 
xe2x80x83wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R3 is selected from the group consisting of straight or branched chain alkyl of from 1 to 4 carbon atoms, aliphatic cyclic compound of from 5 to 7 carbon atoms, and benzyl: 
xe2x80x83wherein
n is an integer from 0 to 2;
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
X is imidazole, triazole, or tetrazole moiety having the following formula (XII): 
xe2x80x83wherein
n is 0 ; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R4 is selected from the group consisting of straight or branched chain alkyl of from 1 to 3 carbon atoms, phenyl and benzyl.
It is another object of the present invention to provide a pharmaceutical composition comprising an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds represented by the above structural formula (I), in particular, the compounds represented by the above structural formula (V), (VIII), (XIV) and (XVI), for treating disorders of central nervous system such as psychosis and cognition disorder.
It is still another object of the present invention to provide a method of treating disorders of central nervous system such as psychosis and cognition disorder in a mammal by administering an effective amount of racemic or enantiomerically enriched benzoyl piperidine compounds represented by the above structural formula (I), in particular, the compounds represented by the above structural formula (V), (VIII), (XIV) and (XVI) and a pharmaceutical acceptable carrier to a mammal in need of psychosis and cognition therapy.
In accordance with the present invention, the compound represented by the structural formula I and pharmaceutical acceptable salts thereof can be prepared by the following steps starting from amino alcohol compounds represented by the following general structural formula (II): 
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl and phenyl; thienyl; naphthyl; pyridyl; and quinolyl; and
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms.
The method for preparing the amino alcohol compounds represented by the general structural formula (II) will be described below in detail.
Reacting epoxide represented by the following structural formula (III); 
wherein n and A are the same as defined above;
with benzoyl piperidine represented by the following structural formula (IV): 
wherein Y is the same as defined above;
to synthesize amino alcohol compounds represented by the structural formula (II).
It should be noted that the stereochemistry of the product (I, II, V, VIII, XIV and XVI) depends solely on that of the starting material (III); a starting material (III) with an (S)-enantiomer yields only a product with (S)-enantiomer and a starting material (III) with an (R)-enantiomer yields only a product with (R)-enantiomer.
The method for preparing the O-carbamoyl benzoyl piperidine compounds represented by the following general structural formula (V) will be described below in detail. 
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R1 and R2 may be the same with or different from each other and are independently selected from the group consisting of hydrogen, methoxy, benzyl and 5 to 7-membered aliphatic cyclic compounds.
The O-carbamoyl benzoyl piperidine compounds represented by the general structural formula (V) are prepared by reacting amino alcohol represented by the general structural formula (II) with 1,1xe2x80x2-carbonyldiimidazole and then with amine base represented by the following general structural formula (VI);
R1R2NHxe2x80x83xe2x80x83(VI)
wherein R1 and R2 are the same as defined above.
This procedure is summarized as set forth in Reaction Scheme I below. 
Details of the reaction conditions described in Reaction Scheme I are as follows. For the conversion of the compounds (II) to the compound (V), the concentration of the starting material (II) is about 0.005 to 0.1 moles with 1,1xe2x80x2-carbonyldiimidazole ranging from about 2.0 to 3.0 equivalents. This reaction is preferably carried out at a temperature of 10 to 30xc2x0 C. Without purification, the resulting intermediate is treated with 1 to 1,000 equivalents of amine base represented by the general formula (VI) at a temperature of 10 to 30xc2x0 C. to give the compound of the general formula (V). For this carbamoylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme I, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom. Specific examples of the anhydrous acid used for the preparation of the compound (VII) from the compound (V) include hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, benzoic acid, citric acid, malonic acid, salicylic acid, malic acid, fumaric acid, oxalic acid, succinic acid, tartaric acid, lactic acid, gluconic acid, ascorbic acid, maleic acid, aspartic acid, benzene sulfonic acid, methane sulfonic acid, ethane sulfonic acid, hydroxymethane sulfonic acid and hydroxyethane sulfonic acid and the like. Additional acids can refer to xe2x80x9cPharmaceutical Saltsxe2x80x9d, J. Pharm. Sci., 1977; 66(1): 1-19. This preparation is executed in a reaction media which can be exemplified by an ethereal solvent such as tetrahydrofuran, an alcoholic solvent such as.methanol, an ester solvent such as ethyl acetate, a halogenated hydrocarbon solvent, and the mixtures thereof. An ethereal solvent is recommended as an addition solution, including ethyl ether, propyl ether, isopropyl ether, butyl ether, isobutyl ether. The concentration of the compound (V) is on the order of about 0.01 to 5 moles.
The method for preparing the alkoxy benzoyl piperidine compounds represented by the following general structural formula (VIII) will be described below in detail. 
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from. 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano, trifluoromethyl, trifluoromethoxy, methanesulfonyl, phenyl; thienyl; naphthyl; pyridyl; and quinolyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R3 is selected from the group consisting of straight or branched chain alkyl of from 1 to 4 carbon atoms, aliphatic cyclic compound of from 5 to 7 carbon atoms, and benzyl.
The alkoxy benzoyl piperidine compounds represented by the general structural formula (VIII) is prepared by reacting amino alcohol represented by the general structural formula (II) with methanesulfonyl chloride and triethylamine and then with alcohol represented by the following general structural formula (IX);
R3OHxe2x80x83xe2x80x83(IX)
wherein R3 is the same as defined above.
The alternative method for conversion of amino alcohol compounds (II) to alkoxy benzoyl piperidine compounds of the general structural formula (VIII) in which A is phenoxy is to react amino alcohol represented by the general structural formula (II) with sodium hydride and then with alkyl halide represented by the following general structural formula (X) to produce alkoxy benzoyl piperidine compounds represented by the general structural formula (VIII);
R3Zxe2x80x83xe2x80x83(X)
wherein Z is a halogen atom such as chloride, bromide or iodide.
The pharmaceutically acceptable salts thereof can be obtained by treating alkoxy benzoyl piperidine compounds (VIII) with an anhydrous acid in a solution without further purification.
This procedure is summarized as set forth in Reaction Scheme II below. 
Details of the reaction conditions described in Reaction Scheme II are as follows. For the conversion of the compounds (II) to the compound (VIII), the concentration of the starting material (II) is about 0.005 to 0.1 moles with methanesulfonyl chloride ranging from about 3.0 to 4.0 equivalents and triethylamine ranging from about 3.0 to 4.0 equivalents. This reaction is preferably carried out at a temperature of 0 to 30xc2x0 C. Without purification, the resulting intermediate is treated with 1 to 1,000 equivalents of alcohol represented by the general formula (IX) at a temperature of 30 to 90xc2x0 C. to give the compound of the general formula (VIII). For this alkylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, an alcohol solvent such as methanol, ethanol and propanol, or the mixture thereof may be used.
For the alternative conversion of compound (II) to the compound (VIII) in which A is phenoxy, the concentration of the starting material (II) is about 0.01 to 0.1 moles with sodium hydride ranging from about 1.0 to 2.0 equivalents. The mixture is treated with 1.0 to 2.0 equivalents of alkyl halide represented by the general formula (X). This reaction is preferably carried out at a temperature of 0 to 20xc2x0 C. For this alkylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme II, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom.
The method for preparing the azole benzoyl piperidine compounds represented by the general structural formula (XIV) in which X is imidazole, triazole or tetrazole moiety having the following general structural formula (XII) will be described below in detail. 
wherein
n is an integer from 0 to 2;
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro and trifluoromethyl; and naphthyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
X is imidazole, triazole, or tetrazole moiety having the following formula (XII): 
The azole benzoyl piperidine compounds represented by the general structural formula (XIV) in which X is imidazole, triazole or tetrazole moiety having the general structural formula (XII) is prepared by reacting amino alcohol represented by the general structural formula (II) with methanesulfonyl chloride and triethylamine and then with azole represented by the following general structural formula (XIII): 
The pharmaceutically acceptable salts thereof can be obtained by treating azole benzoyl piperidine compounds with an anhydrous acid in a solution without further purification.
This procedure is summarized as set forth in Reaction Scheme III below. 
Details of the reaction conditions described in Reaction Scheme III are as follows. For the conversion of the compounds (II) to the compound (XIV) in which X is imidazole, triazole or tetrazole moiety having the general structural formula (XII), the concentration of the starting material (II) is about 0.005 to 0.1 moles with methanesulfonyl chloride ranging from about 1.0 to 3.0 equivalents and triethylamine ranging from about 1.0 to 3.0 equivalents. This reaction is preferably carried out at a temperature of 0 to 30xc2x0 C. Without purification, the resulting intermediate is treated with 3 to 4 equivalents of azole represented by the general formula (XIII) at a temperature of 30 to 90xc2x0 C. to give the compound of the general formula (XV). For this reaction, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme III, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom.
The method for preparing the carbonate benzoyl piperidine compounds represented by the following general structural formula (XVI) will be described below in detail. 
wherein
n is 0; and
A is selected from the group consisting of phenyl which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl; or
n is an integer from 1 to 2; and
A is selected from the group consisting of phenyl or phenoxy which may be substituted with one or more identical or different substituents selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, straight or branched chain alkoxy of from 1 to 3 carbon atoms, nitro, cyano and trifluoromethyl;
Y is selected from the group consisting of hydrogen, halogen, straight or branched chain alkyl of from 1 to 4 carbon atoms, and straight or branched chain alkoxy of from 1 to 3 carbon atoms; and
R4 is selected from the group consisting of straight or branched chain alkyl of from 1 to 3 carbon atoms, phenyl and benzyl.
The carbonate benzoyl piperidine compounds represented by the general structural formula (XVI) is prepared by reacting amino alcohol represented by the general structural formula (II) with 1,1xe2x80x2-carbonyldiimidazole and then with alcohol represented by the following general structural formula (XVII):
R4OHxe2x80x83xe2x80x83(XVII)
wherein R4 is the same as defined above.
The pharmaceutically acceptable salts thereof can be obtained by treating carbonate benzoyl piperidine compounds with an anhydrous acid in a solution without further purification.
This procedure is summarized as set forth in Reaction Scheme IV below. 
Details of the reaction conditions described in Reaction Scheme IV are as follows. For the conversion of the compounds (II) to the compound (XVI), the concentration of the starting material (II) is about 0.005 to 0.1 moles with 1,1xe2x80x2-carbonyldiimidazole ranging from about 2.0 to 3.0 equivalents. This reaction is preferably carried out at a temperature of 10 to 30xc2x0 C. Without purification, the resulting intermediate is treated with 1 to 1,000 equivalents of alcohol represented by the general formula (XVII) at a temperature of 10 to 30xc2x0 C. to give the compound of the general formula (XVI). For this carbonylation, an ethereal solvent such as diethyl ether and tetrahydrofuran, a halogenated hydrocarbon solvent such as dichloromethane and chloroform, or the mixture thereof may be used.
In Reaction Scheme IV, HX represents an acid capable of forming a pharmacologically useful salt with the basic nitrogen atom.
Representative examples of the compounds (I), (V), (VIII), (XIV) and (XVI) from scheme I, II, III and IV include the following structures: 
The present invention includes methods of treating psychosis and cognition disorders in a mammal which comprises administering the composition of the compound of structural formula (I), (V), (VIII), (XIV) and (XVI) to a mammal in need of psychosis and cognition therapy.
This activity was examined through the anti-climbing behavior test, i.e. the test for suppressing the climbing behavior induced by apomorphine in mice. A designated amount of the test compound was intraperitoneally or orally administered to several groups of ICR CD strain male mice (body weight, 20 to 25 g; one group, 6 mice), and each of the animals was charged in an individual column cage of 12 cm in diameter and 14 cm in height having metal poles (each pole, 2 mm in diameter) vertically installed and arranged along the periphery with interval of 1 cm.
Compounds to be tested for antipsychotic activity are injected intraperitoneally or given orally at various time intervals, e.g. 30 minutes, 60 minutes, etc., prior to the apomorphine challenge at a screening dose of 0.1-60 mg/kg.
For evaluation of climbing, 3 readings are taken at 10, 20 and 30 minutes after apomorphine administration according to the following scale:
Mice consistently climbing before the injection of apomorphine will be discarded.
With full-developed apomorphine climbing, the animals are hanging on to the cage walls, rather motionless, over longer periods of time. By contrast, climbing due to mere motor stimulation usually only lasts a few seconds.
The climbing scores are individually totaled (maximal score: 12 per mouse over 3 readings) and the total score of the control group (vehicle intraperitoneally-apomorphine subcutaneously) is set to 100%. ED50 values with 95% confidence limits, calculated by a linear regression analysis, of some of the compounds of the instant invention as well as a standard antipsychotic agent are presented in Table I.
In therapeutic use as agents for various CNS disorders such as psychosis and cognition disorder, the compounds of the present invention, alone or in combination with pharmaceutically acceptable carrier, are administered to patients at a dosage of from 0.7 to 7,000 mg per day. For a normal human adult with a body weight of approximately 70 kg, the administration amount is translated into a daily dose of 0.01 to 100 mg per kg of body weight. The specific dosage employed, however, may vary depending upon the requirements of the patient, the severity of patient""s condition and the activity of the compound. The determination of optimum dosages for a particular situation must clinically be done and is within the skill of the art.
In utilizing the compounds of the present -invention for the central nervous system, it is preferred to administer the compounds orally. Since the compounds absorb well orally, it usually will riot be necessary to resort to parenteral administration. For oral administration, the compounds having the general formula I is preferably combined with a pharmaceutical carrier. The ratio of the carrier to the compound of structural formula I is not critical to express the effects of the medicine on the central nervous system, and they can vary considerably depending on whether the composition is to be filled into capsules or formed into tablets. In tableting, various edible pharmaceutical carriers or the mixture thereof can be used. Suitable carriers, for example, are a mixture of lactose, diabasic calcium phosphate and/or corn starch. Other pharmaceutically acceptable ingredients can be further added, including lubricants such as magnesium stearate.